Chapman-type layer shapes have been a foundation in ionospheric physics since the formalism was first proposed, due to both a simple functional form and an underlying physical basis in solar production. In this report, a new means for utilizing these convenient layer shapes is described for the specification of electron density profiles, wherein both the topside and bottomside are approximated by Chapman layers of varying scale heights. Permitting the scale height to vary is essentially a mathematical means of accounting for the changes in layer shapes from the purely solar-produced value to changes produced in the presence of diffusive transport, while retaining the overall numerical convenience of the Chapman formalism. This profile model has first been applied to a sample of electron density profiles obtained at the Millstone Hill, Massachusetts, incoherent scatter radar, to establish credibility of the profile formalism with respect to real profiles. Next, the formalish was applied to a database of theoretical ionospheres from the Phillips Laboratory Ionospheric Model, to develop a model along the lines of the Semiempirical Low-latitude Ionospheric Model that is (1) more authentic to the original model runs, (2) more accurate in terms of total electron content, and (3) applicable over a wider latitude range. ¿ American Geophysical Union 1994